Engine cylinder construction



W. E, BRILL.

ENGINE CYLINDER CONSTRUCTION Dec. ll, 1945.

Filed NOV. l5, 1942 Patented Dec. l1, 1945 2,390,637 ENGINE CYLINDER CONSTRUCTION william Elmer Brul, cleveland, ohio, assigner to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application November'13, 1942, Serial No. 465,453

(Cl. 12S-65) 4 Claims.

'I'he 'present invention relates generally to internal combustion engines, more especially to a cylinder liner construction for light weight, high-v and ports of suitable dimensions therein. Thisincrease in outside diameter and weight of the Vcylinder liners accordingly increases the dimensions of the engine and its weight materially.

'I'he principal object of the present invention is to provide a light weight welded cylinder liner for a two stroke internal combustion engine in which frustum shaped scavenging and charging ports may be easily and accurately formed to provide efliclent scavenging of the liner and to provide cooling passages for the liner of small radial dimensions to insure rapid axial circulation of coolant therethrough and to also reduce the overall diameter of the liners thereby reducing the dimensions and weight of the engine incorporating cylinders of this type. Y

The liner construction providing the above mentioned objects will be better understood by reference to the following detailed description thereof and the accompanying drawing illustrating a construction suitable for a two stroke engine having exhaust valves in the cylinder heads. It will be evident from the following that the type of liner described and illustrated maybe modified to adapt it to other types of machines.

Figure 1 of the drawing is a vertical sectional view of the liner construction taken on line I-I of Figure 2.

Figure 2 is a transverse cross sectional View taken on line 2--2 of Figure 1.

Figure 3 is a transverse cross sectional view taken on line 3-3 of Figure l, and,

Figure iis a broken away view taken on line 4--4 of Figure 3.

Referring to Figure 1, the cylinder liner assembly includes an internal sleeve I having an internal bore in which the engine piston, not shown, reciprocates and the external cylindrical surface of the sleeve is provided with ltwo axially spaced lands 3 and 5 of slightly greater diameter and also cooling and stiffening iins 1 and a lower mounting flange 9.0i a diameter slightly less than the lands 3 and 5. 'I'he land 3 is of sufcient axial length to allow a plurality of circumferentially spaced frustum shaped scavenging and charging air ports Il to be easily formed therein in a manner to be described.` These ports are uncovered by movement of the piston to bottom dead center to allow scavenging and charging .zir to enter the sleeve I through these ports in conventional manner.

An upper mounting flange I3 is pressed on the upper, or head end of the sleeve I and this flange is provided with a downwardly extending cylindrical portion I4 having an internal diameter greater than that of the sleeve I adjacent thereto and an outside diameter substantially equal to that of the lands 3 and 5. A corrugated sleeve I5 serving as an upper coolant jacket is welded between the portion I 4 of the upper mounting ange I3 and the upper portion oi.' the land 3 to form-a coolant space above the ports II and another corrugated sleeve or coolant jacket I1 is welded between the lower portion of the land 3 and the lower land 5 to form a. coolant space below the ports I I. Coolant passages .comprising groves I9 extending axially across the land 3 between certain of the ports II serve to connect the coolant spaces either side of the ports. These passages or grooves have plates 2| of suicient axial length and circumferential width to be welded to the land 3 either side of the grooves I9 and to the upper and lower sleeves or jackets to allow rapid circulation of the` coolant axially through the above described coolant passages above, between and below the ports II, as the radial dimension of these passages is small.

The coolant enters these passages through an inlet port 23 in the upper mounting flange I3 and passes outward through a plurality of outlet ports drilled therein, one of which is shown at To insure proper controlled circulation of the coolant axially through the coolant passages a bafile plate 21, as best shown in Figures 1, 3 and 4, is welded on the inner surface of the upper mounting flange portion I3 adjacent the coolant inlet port 23. The upper portion of the baille adjacent the port 23 is curved and the lower portion extends downward between the upper jacket I5 and sleeve I to a point slightly aboveyat least one of the coolant passages I9 between adjacent ports II.

In addition to the means described above for obtaining controlled and rapid circulation of the coolant both axially and circumferentially along the sleeve I and between the ports II which like- Wise enables the outside diameter of the assembly to be only slightly greater than the bore of the cylinder I, the frustuin shaped scavenging and charging ports previously mentioned are layed out inthe following manner so that they may be easily and accurately cut without distortion oi' the thin walled internal sleeve I and to also cause the air entering each of these ports to be directed toward a point A located within the sleeve I and displaced from the axis ofthe sleeve. Point A for each port I I is located as best shown in Figuref2 at the intersection of lines a and b drawn tangent to circles of smaller diameter than the internal diameter of the sleeve A and B and concentric therewith. It will be evident that by mounting a suitable cutting tool such as a burning torch on a ball joint whose center is at point A and limiting the horizontal and vertical movement thereof by means of a ilxed template of rectangular shape, the ports II of similar shape may be accurately formed and that the contour of the peripheral surface of these ports will be of frustum shape lconforming substantially to the lines a, b, c, d. which converge inwardly toward point A as shown in Figures l and 2. It will be evident that the axis of each frustum shaped port is displaced wlthrespect to the longitudinal axis of tha sleeve I. Where a burning torch is used to cut these ports no further machining of the surface is necessary and the torch may be pivoted either at point A and directed outward or ilxed to a suitable pantograph which is pivoted at point A or` at any point in a line extending through point A and parallel to the axis of the sleeve which enables the torch to be directed inward to cut these port openings in either the internal sleeve I, or in both the sleeve I and an outer one piece sleeveor jacket which may be used in place-of the multiple jacket construction described and shown. The general out- `the movement of the torch about point A.

The above described method whereby frustum shaped ports Il may be accurately formed so that the peripheral surface of each converges inwardly substantially toward a focal point A displaed from the axis of the sleeve so that the scavenging air entering the cylinder sleeve through a port will be directed substantially to, or focused on point A to cause circular movement of the air within the sleeve I. With a plurality of such ports circumferentially spaced in the cylinder sleeve I, .and exhaust valves located in the cylinder head efllcient vortex or rotary end to end scavenging and charging o1' the cylinder sleeve will be provided.

I claim:

1. A hollow cylinder having a plurality of circumferentially spaced iluid entrance ports, said ports being of frustum shape for causing the fluid entering said ports to converge Atoward separate points within said cylinder, said separate points being located in a plane transverse to the cylinder axis.v y

2. A hollow cylinder having a, plurality of circumferentially spaced frustum shaped fluid entrance ports, the axes of said ports being severally displaced with respect to the longitudinal axis of said cylinder and in the mid-plane of the ports to cause fluid entering each of said ports to converge toward a point and thereby cause rotary movement of the iluid in said cylinder about the longitudinal axis of said cylinder.

3. A hollow cylinder having a plurality of circumferentially spa/ced fluid entrance ports of frustum shape, the Wall of each port being projected froma separa-te point within the cylinder and in a plane transverse to the longitudinal axis of said cylinder, each of said points being displaced from the cylinder axis to cause` rotary motion of the fluid within said cylinderby entrance of iluid through said ports.

4. A hollow cylinder having a plurality of circumferentially spaced frustum shaped iluld inlet ports, .the peripheral surface of each of said ports converging inwardly toward a point within the cylinder, said points being uniformly displaced from the longitudinal center line of the cylinder and in the central transverse plane of the ports.

WILLIAM ELMER BRILL. 

